<template>
	<view>
		<view class="scroll-view-container">
			<!-- 左侧 -->
			<scroll-view class="left-scroll-view" scroll-y="true" :style="{height:wh + 'px'}">
				<!-- <view class="left-scroll-view-item active">{{item.cat_name}}</view> -->
				<block v-for="(item, i) in cateList" :key="i">
				    <view :class="['left-scroll-view-item',i === active ? 'active':'']" @click="activeChanged(i)">{{item.cat_name}}</view>
				</block>
			
			</scroll-view>
			<!-- 右侧 -->
			<scroll-view class="right-scroll-view" scroll-y="true" :style="{height:wh + 'px'}" :scroll-top="scrollTop">
				<view  v-for="(item2, i2) in cateLevel2" :key="i2">
					<!-- <view :class="['left-scroll-view-item',i === active ? 'active':'']">{{item.children}}</view> -->
					<view class="cate-lv2-title">/ {{item2.cat_name}} /</view>
					<!-- 三级分类列表 -->
					<view class="cate-lv3-list">
						<!-- item -->
						<view calss = "cate-lv3-item" v-for="(item3,i3) in item2.children" :key="i3" @click="gotoGoodsList(item3)">
							<!-- iamge -->
							<image :src="item3.cat_icon"></image>
							<!-- text -->
							<text>{{item3.cat_name}}</text>
						</view>
					</view>
				</view>
			
			</scroll-view>
		
		</view>
	</view>
</template>

<script>
	export default {
		data() {
			return {
				wh:0,
				active:0,
				cateList:[],
				// 二级分类列表
				cateLevel2: [],
				// 滚动条距离顶部的距离
				scrollTop: 0
			};
		},
		onLoad() {
			const systemInfo = uni.getSystemInfoSync();
			this.wh = systemInfo.windowHeight - 50
			this.getCateList()
		},
		methods:{
			async getCateList(){
				const {data:res} = await uni.$http.get('/api/public/v1/categories')
				// 判断是否获取失败
				if (res.meta.status !== 200) return uni.$showMsg()
				// 存储数据
				this.cateList = res.message
				// 为二级分类赋值
				this.cateLevel2 = res.message[0].children
			},
			// 选中项改变的事件处理函数
		  activeChanged(i) {
			this.active = i
			// 为二级分类列表重新赋值
			this.cateLevel2 = this.cateList[i].children
			// 让 scrollTop 的值在 0 与 1 之间切换
			  this.scrollTop = this.scrollTop === 0 ? 1 : 0
		  },
		  // 点击三级分类项跳转到商品列表页面
		  gotoGoodsList(item3) {
		    uni.navigateTo({
		      url: '/subpkg/goods_list/goods_list?cid=' + item3.cat_id
		    })
		  }
		}
	}
</script>

<style lang="scss">
	
	.scroll-view-container{
		display: flex;
		.left-scroll-view{
			width: 120px;
		}
		.left-scroll-view-item{
			line-height: 60px;
			background-color: #f7f7f7;
			text-align: center;
			font-size: 12px;
			
			&.active{
				background-color: #ffffff;
				position: relative;
				 // 渲染激活项左侧的红色指示边线
				&::before {
				  content: ' ';
				  display: block;
				  width: 3px;
				  height: 30px;
				  background-color: #c00000;
				  position: absolute;
				  left: 0;
				  top: 50%;
				  transform: translateY(-50%);
				}
			}
		}
		.cate-lv2-title{
			font-size: 12px;
			font-weight: bold;
			text-align: center;
			padding: 15px 0;
		}
		
	}
	
	.cate-lv3-list{
		display: flex;
		flex-wrap: wrap;
		
		  .cate-lv3-item {
		    width: 33.33%;
		    margin-bottom: 10px;
		    display: flex;
		    flex-direction: column;
		    align-items: center;
		
		    image {
		      width: 60px;
		      height: 60px;
		    }
		
		    text {
		      font-size: 12px;
		    }
		  }
	}

</style>
